In the automotive industry, in particular, it has become increasingly necessary to combine multiple functions in a single heat exchanger assembly. The need to reduce the number of overall components and to optimize assembly efficiency has driven the need for improved heat exchanger devices that combine increasingly efficient designs and multiple functions in packaging heretofore attainable using plural separate components or devices having inefficient designs. More specifically, there has been a growing need for an improved heat exchanger device, particularly for under the hood automotive vehicle applications, which combines multiple functions in a single assembly that is efficient to make and operate and that occupies substantially the same or less space than existing heat exchanger devices. Due to relatively recent advancements in the field, including, in particular, the development of combination heat exchanger assemblies or ‘combo coolers’, there is also a need to develop systems of more than one baffle to insure that multiple fluids be maintained basically separated from one another.
As stated above, particularly where a multi-fluid heat exchanger is to be employed, it is attractive to be able to maintain each of the different fluids of the exchanger separated from each other. The employment of baffles is one possible approach. However, until the present invention, double baffle designs have often resulted in space problems, and the like, contributing to the loss of function or efficiency of one or more of the heat exchanger tubes. In particular, certain heat exchanger assemblies may have space requirements that extend to at least one core tube-end in the tank.
Furthermore, in multi-fluid heat exchanger assemblies, an internal solution has often been to insert, during assembly, at least two separate pieces, to form a so called double baffle. A first and a second baffle can be assembled back to back with a common center contact portion.
Such a double baffle is in actuality, therefore, a double piece double baffle, as the two separate baffles have a space between the pieces to ensure that one fluid in the separate fluid systems remains separated from the other. To provide most effective functioning of such a system, a ‘weep hole’ must often be placed on the cover surface of the heat exchanger manifold, between the pieces of the double baffles, in order to let flux enter prior to brazing and to serve a potential leak detection function. This has caused a problem, however, since the double piece double baffle needs to be affixed in some manner to maintain its position to perform their function, and positional control needs to be optimized to allow for reduced tube pitches, especially in higher performance heat exchanger assembly applications. Thus, it would be especially desirable for an improved baffle design that can be incorporated into a heat exchanger, and particularly a multi-fluid heat exchanger, which makes efficient use of all heat exchanger tubes and solves this positional control problem.
As described above, some automotive heat exchangers have evolved to contain two or more separate fluids for heat exchange, the fluids separated by a baffle internal to the heat exchanger. It is an object of the present invention, therefore, to keep multiple fluids within a multi-fluid heat exchanger separate, and, if unsuspected or inadvertent leaks do occur, to insure that internal fluids remain separated, so that a leaking fluid ‘leaks’ to the exterior or atmosphere outside of the heat exchanger and not into an internal area of the heat exchanger where it could mix with or ‘contaminate’ other fluids.
Thus, it would be especially desirable for an improved double baffle design that can be incorporated into a heat exchanger, and particularly a multi-fluid heat exchanger, which remains efficient while keeping the fluids separated from one another. It would also be desirable to provide for a heat exchanger with baffles that keep fluids separated such that a leak of one or more fluids from the heat exchanger will not result in a contamination of any other fluid inside the heat exchanger, since cross contamination can lead to catastrophic failure of one or more on the systems cooled by a heat exchanger.
As disclosed above, it has been found that leaks and mixing or contamination between fluids can lead to inefficient or less that optimal heat exchanger performance, as well as damage to the vehicle and customer discomfort. There are problems with heat exchanger designs, and especially heat exchanger designs that employ multiple baffles, as some of the designs solve the problem of leaks by allowing leaks to the atmosphere; while subsequently providing for two separate baffles with spaces in-between to avoid the problem of leaks between the parts of the exchanger. However, such designs either take up a large amount of space (EP0789213) or do not allow an adequate gap or space to efficiently function.
In addition, the gaps or spaces between the baffles are susceptible to filling with flux and/or braze materials during manufacture during the braze cycle. The result of such gap filling can lead to temporary blockages of the gap or space, meaning that the fluids, in case of leak at the double baffle, cannot leak through the gap or space into the atmosphere, and, therefore, lead to inefficient or less effective functioning.